Our results aim to inform current debates about early belief simulation (Baillargeon et al., 2018), its developmental trajectory (Grosse-Wiesmann & Southgate, 2024) and its evolution in human and nonhuman great apes.

This developmental pattern resembles closely the one found in humans. We conclude that the susceptibility to altercentric influences is not a uniquely human feature but is deeply rooted in great ape cognition.

While we found that even adult apes were influenced in their search behaviour by the false belief of a bystander, replicating the findings by Lurz et al., (2022), we show that infant apes were influenced the strongest.

These patterns highlight how both cultural context and information source shape strategy updating, with important implications for understanding learning and adaptation across cultural development. Congratulations to everyone involved—especially to the 1st author Wilson Vieira for this hard work!

Culture and age matter. We observed developmental differences: flexibility decreased with age in BaYaka children, but the opposite pattern emerged among German children. Overall, German kids were more flexible than their Congolese peers.

Social learning can suppress flexibility. When children learned solutions by watching others, they were more likely to stick with old strategies—even when better options emerged.

While adult apes remembered the object better when it was associated with a social stimulus, infant apes showed no such memory improvements. However, after a 2-day delay, the social memory effect of the adults disappeared.